This digital data set, compiled from new 10-meter digital elevation model (DEM) data, represents the physiography of the Willamette Valley, Oregon. This new physiographic data is useful because the improved resolution allows for better visualization of flood and fluvial features in the low lying areas of the Willamette Valley. Many scientist are interested in the Willamette Valley because it is subject to a variety of earthquake hazards, and its water and geologic resources are under pressure from rapid urbanization (see sheets for a brief description). Further, this Open-File report details the techniques used to create these maps (See readme.pdf). It is the author's purpose to publish these techniques and data so others may use this report to generate their own gray scale and/or color shaded-relief maps. All information about the data and methods used to create this report are in the readme.pdf file and this document.

This digital dataset was compiled from newly released U.S. Geological Survey 10-meter digital elevation model (DEM) data, along with stream and transportation coverages previously published on the internet. This report consists of a digital representation of the physiography of the Willamette Valley. Contained in this dataset is: 1) 10-meter DEM data for the entire Willamette Valley; 2) the ARC/INFO grids used to create the color shaded-relief and gray scale shaded-relief images; 3) the necessary data ARC/INFO data to used to plot these data; and 4) several reports detailing the data formats (this docuement) and producers used to create these datasets. The scale of the original 10-meter DEM data should not be violated. Any use of these original data smaller than the intended scale (1:24,000) will not yield improved accuracy.

The databases in this report were compiled in ARC/INFO, a commercial Geographic Information System (Environmental Systems Research Institute, Redlands, California, with version 3.0 of the menu interface ALACARTE (Fitzgibbon and Wentworth, 1991, Fitzgibbon, 1991, Wentworth and Fitzgibbon, 1991). The files are in either GRID (ARC/INFO raster data) format or COVERAGE (ARC/ INFO vector data) format. Coverages are stored in uncompressed ARC export format (ARC/INFO version 8.0.2). ARC/INFO export files (files with the .e00 extension) can be converted into ARC/ INFO coverages in ARC/INFO (see below) and can be read by some other Geographic Information Systems, such as MapInfo via ArcLink and ESRI's ArcView (version 1.0 for Windows 3.1 to 3.11 is available for free from ESRI's web site: http://www.esri.com). The digital compilation was done in version 8.0.2 of ARC/INFO with version 3.0 of the menu interface ALACARTE (Fitzgibbon and Wentworth, 1991, Fitzgibbon, 1991, Wentworth and Fitzgibbon, 1991). Custom AMLs were written to compile the 10-meter DEM data from 7.5-minute quadrangles into large composite datasets. The data was compiled as ARC/INFO grids and then converted to decimeter integer grids. This procedure greatly reduces the file sizes without downgrading the data quality. Stream coverages were merged with the grids used to create the color shaded-relief grid composite. Further details on the techniques used to generate these maps are available in the readme file of this report.

This is a dataset download, not a document. The Open button will start the download.Digital Elevation Model. 10m pixels. Elevation values in feet. Elevation data assembled from merged 7.5-minute DEM blocks (10- by 10-m data spacing).

Scoggins Dam in northwest Oregon lies within the Gales Creek fault zone (GCF), a northwest-striking system of active faults forming the boundary between the Coast Range and the Tualatin Valley about 25 km east of Portland, Oregon. Geologic mapping published in 2020 shows the dam to lie within a block-faulted releasing stepover between the right-lateral, NW-striking Scoggins Creek and Parsons Creek strands of the GCF. The Scoggins Creek strand is presently mapped beneath the existing dam about 200 m north of the south abutment. Preliminary results from paleoseismic trenching by the U.S. Bureau of Reclamation, Portland State University, and the U.S. Geological Survey indicate that these two major fault strands have had multiple surface rupturing earthquakes in the Holocene. To confirm the accuracy of the 2020 geologic map and the geometry of the GCF in the releasing stepover region, we completed additional geologic mapping of the dam, reservoir, and an alternative dam site downstream between July 2018 and May 2020. Using high-resolution lidar topographic data and satellite imagery on handheld digital tablets, we collected data at ~500 field sites in the heavily forested terrain. We used these detailed field observations to locate and digitally map the main Scoggins Creek and Parsons Creek fault strands, as well as the cross faults linking the two main strands, to produce an improved and more detailed geologic map and cross sections of Scoggins Valley and its existing and proposed dam sites.

The basis for these features is U.S. Geological Survey Scientific Investigation Report 2017-5024 Flood Inundation Mapping Data for Johnson Creek near Sycamore, Oregon. The domain of the HEC-RAS hydraulic model is a 12.9 mile reach of Johnson Creek from just upstream of SE 174th Avenue in Portland, Oregon to its confluence with the Willamette River. Some of the hydraulics used in the model were taken from Federal Emergency Management Agency, 2010, Flood Insurance Study, City of Portland, Oregon, Multnomah, Clackamas and Washington Counties, Volume 1 of 3, November 26, 2010. The Digital Elevation Model (DEM) utilized for the project was developed from LiDAR data flown in 2015 and provided by the Oregon Department of Geology and Mineral Industries. Bridge decks are generally removed from DEMs as standard practice. Therefore, these features may be shown as inundated when they are not. Judgement should be used when estimating the usefulness of a bridge during flood flow. Comparing the bridge to the surrounding ground can be more informative in this respect than simply looking at the bridge itself. Two model plans were used in the creation of the flood layers. The first is a stable model plan using unsteady flow in which the maximum streamflow is held in place for a long period of time (a number of days) in order to replicate a steady model using an unsteady plan. The stable model plan produced the areas of uncertainty contained in the sycor_breach.shp shapefile. The second is an unstable model plan that uses unsteady flow in which the full hydrograph (rising and falling limb) is represented based on the hydrograph shape of the December 2015 peak annual flood. The unstable model plan produced the flood extent polygons contained in the sycor.shp shapefile and the depth rasters and represents the best estimate of flood inundation for the given streamflow at U.S. Geological Survey streamgage 14211500.

The DLG described in this document has been produced for use in a statewide base map series for the State of Texas. This metadata document describes a Hypsography digital line graph (DGL-3) file produced by Titan Systems Corp. of Portland, OR for the Texas Strategic Mapping Program (StratMap). StratMap is administered by the Texas Water Development Board (TWDB) and managed by its Texas Natural Resources Information System (TNRIS) division. StratMap was created to produce seven digital base map layers for Texas. StratMap is supported by contributions from the federal government, the State of Texas, and local and regional organizations. The DLG products produced for StratMap and the Texas Water Development Board under the Texas StratMap Program reside in the public domain. As described by USGS's Standards for Digital Line Graphs, a digital line graph is a vector file of large-scale data primarily from 1:24,000 scale USGS topographic quadrangles.

Overlay Zone. There are several contours within the zone. The boundaries of the 65 DNL and 68 DNL noise contours are based on the 1990 Portland International Airport Noise Abatement Plan. The 55 DNL noise contour is based on the 2035 50th Percentile Forecast Noise Exposure Map in the 2010 Portland International Airport Master Plan Update. A set of quarter-section maps, known as the PDX Noise Zone Maps, is available for viewing at the Development Services Center. The maps are the official reference maps for the PDX Noise Zone regulations. The maps show the 55 DNL noise contour and each successively higher noise contour in one DNL increments. https://www.portlandoregon.gov/bps/article/53357-- Additional Information: Category: Zoning Code Purpose: Map location of noise DNLs for application of regulations. Update Frequency: Not Updated-- Metadata Link: https://www.portlandmaps.com/metadata/index.cfm?=DisplayLayer=53427